The June court ruling against teacher employment laws in California was the opening salvo in a battle that has already moved to New York and will likely spread from there. It also could mark the beginning of a third great era of U.S. education reform -- one that focuses not on inputs or outcomes but on the workings of schools themselves.

Moments before closing arguments began in the landmark case Vergara v. California, Judge Rolf Treu asked those in his courtroom to stand, turn and look at two portraits: one of U.S. Supreme Court Chief Justice Earl Warren, the other of California Supreme Court Chief Justice Donald Wright.

He reminded everyone that Warren led the high court to unanimity in Brown v. Board of Education, which marked the beginning of the end of segregation in U.S. public schools. Then he noted that it was Wright who led the state Supreme Court when, in Serrano v. Priest, it invalidated California's uneven school financing system.

"Both decisions have an impact on what we're doing here today," he noted.

Not long afterward, Treu added Vergara to that pantheon. In the most explosive education-related court ruling in a generation, he invalidated several laws dear to California teachers unions, including statutes that provide their members generous tenure rights and seniority protections and specify elaborate and costly procedures required to fire a teacher.

The judge's words were as striking as his verdict: The dismissal statutes prevent firing even "grossly ineffective" teachers whose effect on students "shocks the conscience"; the logic of the "last in, first out" law that prevents job performance from being a factor in layoff decisions is "unfathomable."

Taken as a group, he said, the Vergara statutes particularly harm the most vulnerable: the poor, minority, non-English-speaking students often clustered in low-performing schools.

Teachers unions decried the verdict as an attack on teachers, teaching and public education. Education reformers, who generally view the type of employment statutes at issue in Vergara as contemptible examples of a system that regularly puts the narrow interests of adults before students, celebrated.

Education Secretary Arne Duncan praised the decision, prompting a national teachers union to vote for his resignation. Then he pleaded for collaboration instead of litigation. Yet both camps, knowing the stakes, had already prepared for a multi-state war.

Viewed in wide angle, K-12 education reform in the United States has had two broad, overlapping eras. Both pursued partial solutions and failed to deliver on their promises. The first began in 1954, when Brown struck down unequal access, and continued through decades of lawsuits challenging unequal resources.This era was about inputs, reflecting a belief that if we could just even them out, equitable results would follow. But this hope was misplaced, and de facto segregation and funding disparities live on.

The next era shifted the focus to outcomes. It peaked with the 2001 No Child Left Behind federal statute, which required school systems to measure results. An infrastructure was built to track outcomes and hold educators accountable for them. But the results of these efforts also lagged expectations.

Vergara appears to be the start of a third era focused on the workings of the system itself and the classroom in particular. The classroom is education's ground zero, the place where both student outcomes are generated and the interests of the adults who staff the system will be most deeply affected by the reform of tenure and related statutes.

The ruling's great promise -- and great controversy -- lies in its explicit prioritization of student outcomes over adult interests.

Courts can serve as a moral compass. But in education, delivering on the promise of their rulings typically falls to others: governors, legislators, mayors, school boards, superintendents. Entering this third era of education reform, what should these decision makers be aiming for?

Vergara reveals the path. It reminds us that quality of teaching is the single most important in-school determinant of results. It confirms that the right to a quality education is ultimately fulfilled by highly effective teachers. It makes acutely clear that placing such a teacher in front of every child is the single greatest responsibility of our education system. And this, at its core, is Vergara's promise.

Yet delivering on that promise will require more than invalidating anachronistic labor statutes. We must build, root and branch, a modern human capital system for public education.

Our system needs to do several things well, all of which it now does, at best, inconsistently: successfully train new teachers in schools of education, recruit and retain effective teachers and replace ineffective ones, continuously prepare all teachers to perform at a high level, place the best teachers where the need is highest, cultivate capable administrators and provide teachers and administrators with the tools and autonomy they need to do their jobs well.

We have the knowledge to accomplish all this and strong evidence that, when we do, success will follow. Though the third era of education reform may be the most challenging, it holds the promise that our students are waiting for.

Joshua Lewis, has served on the boards of several for-profit and not-for-profit educational enterprises, including Capella University, New Leaders, New Classrooms and Pearson.